My X1B Project is almost unplayable in X1C: WTF? Any advice

I finally had the chance to open a project (8 different sessions/songs) after upgrading to X1C and I am experience dropouts and skips/pops like crazy. Before this session was fine. My CPU meter (outside of Sonar) even says its only using 15-16% (on my i7). I've put the latencies on my soundcard and inside Sonar up as far as possible - frozen tracks - bounced clips (on transients) and everything else you could think of. There is no reason each one of these projects should be doing this.... and they all are. WTF????? Can anyone help or offer advice?